High speed triplex pump



c. J. coBERLY ETAL 3,077,836

HIGH SPEED TRIPLEX PUMP Feb. 19, 1963 Filed. Feb. l, 1960 10 Sheets-Sheet 1 jira: Z.

Feb- 19, 1963 c. J. coBERLY ETAL 3,077,836

HIGH SPEED TRIPLEX PUMP Filed Feb. l, 1960 l0 Sheets-Sheet 2 20 Is/VEA/raps. AQEMCE l Eea-"ely,

Feb. 19, 1963 c. J. COBERLY ETAL 3,077,336

HIGH SPEED TRIPLEX PUMP Filed Feb. 1. 1960 1o sheets-sheets Feb. 19, 1963 c. J. cosi-:RLY r-:rAL 3,077,836

HIGH SPEED TRIPLEX PUMP Filed Feb. 1, 1960 l0 Sheets-Sheet 4 252 296' v here? 2,0 Mn/QMS,

16a 16:2 H/ems, .755564, Hasse @Kee/w Feb. 19, 1963 c. J. COBERLY ETAL HIGH SPEED TRIPLEX PUMP Filed Feb. l, 1960 l0 Sheets-Sheet 5 Feb. 19, 1963 c. J. coBERLY ErAL 3,077,836

HIGH SPEED TRIPLEX PUMP Filed Feb. 1, 1960 l0 Sheets-Sheet 6 INVEf/ra/Qs L R 0 S E e HM 6 M M H L m 7 E |A j 4 CH. MV) y 5P Mw m if 4 amm 0 0 Z @o 2 L M n w if w Wr 7/ \I P 5. fr -fl/ 1-- j W ,M 4 w Feb. 19, 1963 c. J. coBERLY ErAL 3,077,836

HIGH SPEED `TRIPLEX PUMP Filed Peb. 1, 1960 1o' sheets-sheet 'r ,By Zire/e rram/sgs.

g ,H/Qms, Mew@ )goss-ELL KE/QM Feb- 19, 1963 c. J. coBERLY ErAL 3,077,836

HIGH SPEED TRIPLEX PUMP 10 Sheets-Sheet 8 Filed Feb. 1, 1960 Feb. 19, 1963 c. J. COBERLY ETAL 3,077,836

HIGH SPEED TRIPLEX PUMP l0 Sheets-Sheet 9 Filed Feb. l, 1960 s. M www@ 0 5 umeM f w m Y rfww E OM w c Z @j 4&2 47525@ 445 Feb. 19, 1963 Fiied Feb. 1, 1960 c. J. coal-:RLY ErAL 3,077,836

HIGHSPEED TRIPLEX PUMP 10 Sheets-Sheet 10 ,FZ/n2 26.

United States Patent O 3,077,836 HIGH SPEED TRIPLEX PUB/W Ciarence J. Eoberly, San Marino, and Francis Barton Brown and Carter l. Wiiliarns, La Crescente., Calif., assignors to Kobe, lne., Huntington Park, Caiif., a corporation of California Filed Feb. 1, 196i), Ser. No. 5,840 11 Claims. (Cl. 10S-5) The present invention relates in general to pumps of the reciprocating type capable of delivering uids at high pressures, c g., several thousand pounds per square inch, and relates more particularly to a so-called triplex pump for oil field use to deliver oil under high pressure to uid operated well pumps, to supply water under high pressure for water flooding operations, and the like. However, it will be understood that the triplex pump of the invention may be utilized for other purposes and that various in-l dividual features of the invention may in certain instances have independent utility.

Triplex pumps are well known, one being disclosed in Patent No. 2,081,224, granted May 25, 1937 to Clarence l. Coberly, one of the applicants herein, and Clyde F. Hanson. However, in order to provide a proper background for the objects of the present invention, it is necessary to describe such a conventional triplex pump atleast briefly.

In general, a conventional triplex pump includes three reciprocable pump plungers driven by a crankshaft through lconnecting means which convert rotary mot-ion into reciprocating motion. The housing of such a triplex pump includes a crankcase in which the crankshaft is rotatably mounted and includes a cylinder block which provides three plunger' bores for the three pump plungers, the axes of the plunger bores being perpendicular to the crankshaft axis and lying in a plane containing the crankshaft axis. The cylinder block is located above and is spaced upwardly from the -crankcase by a spacing means through which the three connecting means between the crankshaft and the pump plungers extend, such spacing means conventionally comprising a spacer block superimposed on the crankcase and having the cylinder block superimposed thereon. Each of the connecting means mentioned conventionally includes a crosshead reciprocable in a crosshead guide provided by the triplex pump housing, a connecting rod interconnecting the crankshaft and the crosshead and adapted to convert rotary motion of the crankshaft into reciprocatory motion of the crosshead, and a crosshead stem carried by and extending upwardly from the crosshead and connected to the corresponding pump plunger. The cylinder block is provided with inlets and outlets in communication with the upper ends of the plunger bores and is provided with inlet and outlet check valves `controlling the fiows through the inlets and outlets. A conventional triplex pump also includes, or has associated therewith, various accessories, such as' lubricant pump for delivering lubricating oil from the crankcase to various of the moving parts of the triplex pump, a scavenger pump for scavenging from the spacer block fluid leaking downwardly past the pump plungers, a booster or charge pump for pressurizing the uid delivered to the inlets of the triplex pump, and the like.

A conventional triplex pump has a low crankshaft speed, e.g., 200 to 400 r.p.m., and, as a result, must be a large and heavy affair to provide a useful power output, the result being a low power output per unit of space taken up and a low power output per unit of weight. Also, since prime movers suitable for triplex pump opera-A tion have shaft speeds much higher than the crankshaft speed of a conventional triplex pump, itis necessary to interposey a speed reducer, such as a gear reduction unit, between the. prime mover shaft and the triplex crankshaft, as disclosed in the aforementioned Coberly et al. patent, for example. Such a speed reducer is not only expensive, but it further increases the size and weight of the complete triplex pump installation.

VThe primary object of the present invention is to overcome the foregoing and various other disadvantages of prior triplex pumps by providing a triplex pump which is capable of operating at much higher crankshaft speeds than any heretofore attainable, i.e., which is capable of crankshaft speedsconsiderably in excess of 1000 rpm.

One important result of the high crankshaft speeds attainable with the triplex pump of the present invention is that such speeds correspond to the shaft speeds of prime movers suita-ble for triplex operation. For example, the reciprocating internal combustion engines, such as gas engines, widely used in oil elds have crankshaft speeds ranging generally from 1000 to 1800 r.p.m.

Consequently, the crankshaft of the triplex pump of the present invention can be coupled directly to the prime mover shaft, e.g., the crankshaft of a gas engine, without interposing any speed reducer therebetween, the provision of a prime mover and triplex pump combination having a direct coupling between the prime mover shaft and the crankshaft of the triplex pump being a basic object of the invention. A related object is to provide a gas engine and triplex pump combination wherein the crankshaft of the triplex pump is coupled directly to the crankshaft of the gas engine without any speed reducer or clutch between the triplex pump and the gas engine.

Another result of the high crankshaft speeds of the triplex pump of the invention is a substantial reduction in the size and weight of the triplex pump7 compared to prior, low speed triplex pumps. Expressed differently, the present invention attains a substantially higher power output for the same size and weight as the result of the higher crankshaft speeds. For example, it can be shown that the power outputs, weights and crankshaft speeds of twol triplex pumps being compared are related in accordance with the equation where P1 and P2 are the respective power outputs of the two triplexes, W1 and W2 are the respective weights thereof. and N1 and N2 are the respective crankshaft speeds thereof. As an illustration, the foregoing equation shows that, for the same weight, a triplex having a crankshaft speed of 300 r.p.m. will have a power output of only 40 h.p., whereas a triplex having a crankshaft speed of 1200 r.p.m. will have a power output of h.p. Conversely, it can be shown, by means of the foregoing equation, that, for the same power output, the higher crankshaft speed results in a considerably lower weight.

The lower triplex pump weight attainable with the higher crankshaft speed of the present invention for a given power output permits mounting the triplex pump directly on the prime mover, a primary object of the invention being to provide a triplex pump and prime mover combination wherein the triplex pumpis mounted directly on the prime mover. An important advantage of this construction is that no separate base for the triplex pump is necessary, the prime mover itself serving as the triplex pump base. The elimination .of a separate base results .in a more compact installation having smaller space requirements and results in a further reduction in the overall weight of the installation.

More particularly, an important object of the invention is to provide a prime mover and triplex pump cornbination wherein the housing of the triplex pump is bolted, or otherwise `secured to, the housing of the prime mover with the crankshaft of the triplex pump and the prime mover. shaft disposed an axial alignment and in .end-toend relation, the triplex crankshaft being coupled directly to the prime mover shaft.

Still another object of the invention is to further simplify and enh-ance the compactness of the prime mover and triplex pump combination by mounting various accessories normally associated with and/or forming part of triplex pumps directly on the triplex pump housing so that no separate base therefor is required. More particularly, an important object is to mount a booster or charge pump, for supplying fluid under pressure to the inlets of the triplex pump, directly on the triplex housing with the shaft of the booster pump directly coupled to the crankshaft of the triplex pump. Still more particularly, an object of the invention is to bolt or otherwise secure the booster pump housing to the triplex housing with the shaft of the booster pump in axial alignment with and in end-to-end relation with the triplex crankshaft and to directly couple the booster pump shaft to the triplex crankshaft.

The various objects presented in the foregoing discussion relate more or less generally to the triplex pump of the invention and to its relation to a prime mover on which it is mounted and by which it is driven. The iuvention also involves numerous more specific objects, relating to the triplex pump and its accessories, which will now be outlined briey and which will subsequently be considered in more detail in describing an exemplary embodiment of the invention. Such more specific objects of the invention are to provide an apparatus wherein:

The pump plungers are reciprocable in plunger bores in and are carried by liner assemblies which are readily insertable into and removable from liner bores in the cylinder block to facilitate servicing, changing the diameters of the pump plungers, changing the clearance volumes associated with the pump plungers, and the like;

The liner assemblies are sealed relative to the cylinder block above inlet and outlet ports therein by sealing means which utilize the triplex discharge pressure to pressure load elastomeric sealing elements sufciently that they will not expand and contract excessively when subjected to the alternately high and low pressures in the plunger bores;

Seals are provided between the pump plungers and the liner assemblies adjacent the lower ends of the plunger bores and fluid leaking downwardly past the pump plungers is drawn off above such seals at substantially atmospheric pressure `and is delivered directly from the cylinder block to the scavenger pump, thereby minimizing the quantity of fluid leaking downwardly past the pump plungers which enters the spacer block;

The inlet and outlet check valves controlling the admission and discharge of pumped Huid incorporate various -novel structural details enabling them to operate at the high pressure differentials imposed thereon and at the high frequencies necessitated by the high crankshaft speeds employed;

The inlet and outlet check valves incorporate various novel structural details which result in a long service life despite :the high pressure differentials and high frequencies involved;

'Ihe inlet and outlet check valves are readily insertable into and removable from inlet and outlet valve bores in the cylinder block to facilitate servicing, and the like;

The triplex discharge pressure is utilized to hydraulically maintain the inlet and outlet check valves in their operating positions in the inlet and outlet valve bores;

The inlet and outlet check valves are sealed relative Vto the cylinder block by pressure loaded elastomeric sealing elements in the manner and for the purpose hereinbefore set forth in connection with sealing of the liner assemblies relative to the cylinder blocks;

The inlet check valves have associated therewith means for opening them upon command to yunload the prime mover;

There are no connections between the pump plungers and the crosshead stems so that the crosshead stems merely displace the pump plungers outwardly to effect the working strokes thereof, but do not effect the downward, return strokes of the pump plungers, whereby any damage tending to immobilize one of the pump plungers will merely result in sticking of such pump plunger at the upper end of its travel to eliminate any possibility of damaging the corresponding crosshead stem and crosshead, the crankshaft, or the like;

The return strokes of the pump plungers are effected by the booster or charge pump pressure, the latter being applied to the upper ends of the pump plungers and bein" sufticiently high to cause the pump plungers to follow the crosshead stems downwardly in normal operation;

Contamination of the lubricating oil in the crankcase by downward leakage of the pumped fluid along the crosshead stems and the erossheads is prevented by crosshead-stem sealing means which are effective despite substantial random sidewise movement of the crosshead stems, such random sidewise movement being large at the lhigh crankshaft speeds employed;

The crosshead-stem sealing means are yieldably mounted by resilient means which permit the crosshead-stem sealing means to follow the random sidewise movement of the crosshead stems and which provide fluid-tight seals between the crosshead-stem sealing means and the triplex housing, whereby the random sidewise movement of thc crosshead stems does not break the seals provided by the crosshead-stem sealing means;

Each crosshead-stem sealing means includes two annular sealing elements in huid-tight engagement with the corresponding crosshead stem and spaced apart vertically a distance greater than the stroke of such crosshead stem so that the lower sealing element contacts only the lubricating oil and the upper sealing element contacts only fluid reaching it from above;

Each crosshead-stem sealing means includes pumping means for circulating fluid over the upper side of a sealing element thereof so as to flush contaminants therefrom;

The flushing fluid referred to in the preceding paragraph is constantly filtered to remove contaminants therefrom;

The aforementioned flushing liuid is constantly diluted with clean lluid, and specifically with lubricating oil from the crankcase, to keep the flushing fluid as clean as possible;

The flushing fluid referred to is constantly bled off at a rate such as to and in a manner such as to remove any water with which the flushing uid may become contaminated;

Vapors are scavenged from both the crankcase and the spacer block to prevent lubricating oil contamination by such vapors, the vapor scavenging of the crankcase and the spacer block being effected by a Ventilating means which pumps Ventilating air from the atmosphere first into the crankcase and then from the crankcase into the spacer block;

The Ventilating means for scavenging vapors from the crankcase and the spacer block incldes a hydraulic motor operable by lubricating oil from the crankcase;

The scavenger pump for scavenging liquid leakage of pumped fluid from the spacer block is also connected to the cylinder block in communication with the plunger bores adjacent the lower ends thereof, as hereinbeforc indicated, so as to minimize the quantity of liquid leaking downwardly past the pump plungers which enters the spacer block;

The scavenger pump is a lluid operated pump actuable by a portion of the discharge from the booster or charge pump;

The crossheads are guided in their reciprocatory movement by a crosshead guide or crosshend block which is interposed between and is separate from the crankcase and the spacer block so that, if damaged, or excessively worn, it can be replaced without replacing other components of the triplex housing;

The crosshead block is split into two halves which are adjustably spaced apart so that crosshead guide bores therethrough may be rebored to their original diameter yby reducing the spacing between the crosshead block halves before reboring;

The hydraulic forces tending to displace the cylinder block away from the crankcase as the result of the pressures developed by the pump plungers are applied di rectly to main bearings mounting the crankshaft in the crankcase, this being accomplished by connecting the cylinder block directly to main bearing housings integral with the crankcase;

The lubricating oil in the crankcase is delivered to the various components requiring lubrication by a lubricant pump in the form of a cartridge insertable into a lubricant pump housing integral with the crankcase, whereby no external connections to the lubricant pump are required;

rl`he lubricant pump cartridge is eccentric so that the tension in a chain for driving the lubricant pump from the crankshaft may be varied by rotating the lubricant pump cartridge in its housing;

The coupling means between the triplex crankshaft and the booster pump shaft includes a sprocket on the crankshaft identical to the sprocket thereon for the chain which drives the lubricating pump;

The lubricating oil pressure is maintained constant by a pressure control valve which discharges excess lubricating oil delivered by the lubricant pump back into the crankcase and which may be adjusted while the lubricant pump is in operation;

The crossheads are supplied with lubricating oil from the lubricant pump in such a manner as to constantly center the crossheads in their guide bores through the crosshead block; and

The connecting rod bearings are lubricated from above by the lubricating oil delivered to the crossheads.

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, features and results thereof which will be evident to those skilled in the triplex pump art in the light of this disclosure, may be achieved with the exemplary embodiment of the invention described in detail hereinafter and illustrated in the accompanying drawings, in which:

FlG. l is a perspective view of a gas engine and triplex pump combination of the invention;

FlG. 2 is a diagrammatic view of the engine and triplex combination illustrating the basic components of the pump and the fluid flows therethrough;

FlG. 3 is a side elevational view, partially in vertical section, showing the triplex pump of the invention and the manner in which it is mounted on the gas engine;

FlG. 4 is an enlarged, vertical sectional view which is taken along the arrowed line 4 4 of FlG. 3 and which illustrates one of the three pumping units forming the pumping means of the triplex;

FIG. 5 is a vertical sectional view taken along the arrowed line 5 5 of FlG. 4;

FIGS. 6 and 7 are fragmentary sectional views respectively taken along the arrowed lines 6 6 and 7 7 of FIG. 4;

FIG. 8 is a fragmentary sectional view duplicating a portion of FIG. 7 on an enlarged scale;

FIG. 9 is a fragmentary sectional View taken along the arrowed line 3 9* of FlG. 4;

FIG. l() is a fragmentary vertical sectional view similar to a portion of FlG. 5, but illustrating an alternative construction;

FIG. ll is a fragmentary vertical sectional View which is a downward continuation of FlG. 5;

FlG. l2 is an enlarged, fragmentary horizontal sectional View taken along the irregular arrowed line T12-l2 of FIG. 3;

FIG. 13 is a fragmentary sectional 'View Staken' along' the irregular arrowed line 139-13 of FIG. l2;

FlG. 14 is an enlarged, fragmentary horizontal sectional view taken along the irreguilar arrowed line M ,ld of FIG. 3;

FIG. l5 is a fragmentary sectional -view taken along the irregular arrowed line it-l5 of FIG. 14;

FIG. 16 is an enlarged, fragmentary Vsectional view taken along the arrowed line 16-16 of FIG. 3;

FIG. 17 is a fragmentary sectional View taken along the arrowed line lt'7 ll7 of FlG. 16;

FIGS. 18 and 19 are enlarged sectional views of a crankcase and spacer block Ventilating means embodied in the triplex pump of the invention, FIG. 18 being a transverse sectional View of the Ventilating means which is taken along the arrowed line 8 l8 of FIG. 19, vand FIG. 19 being a longitudinal sectional view of the ventilating means which is taken along the arrowed line 19 l9 of FIG. 18;

FIG. 20 is an enlarged, vertical sectional view taken along the arrowed line 2il 2tl of FlG. 3;

FIG. 21 is an enlarged, fragmentary sectional View taken along the irregular arrowed line Zl-Zll of FIG. 2U;

FIG. 22 is an enlarged, fragmentary sectional view taken along the arrowed line 22-22 of FIG. 20;

FIG. 23 is a fragmentary sectional view duplicating a portion of FlG. 2.2 on a larger scale and with parts in different relative positions than those shown in FIG. 22;

FIG. 24 is a sectional View taken along the arrowed line Zit-24 of FIG. 23;

FIG. 25 is an enlarged, fragmentary sectional view taken along the arrowed line 25 25 of FIG. 3; and

FIG. 26 is an enlarged, fragmentary sectional view taken along the arrowed line 26 26 of FIG. 3, or taken along the arrowed line 26-26 of FIG. 25 of the drawings.

Engine-Triplex Combination Referring particularly to FlGS. 1 to 3 of the drawings, the high speed triplex pump of the invention is designated generally by the numeral 3d and is mounted on and carried by a prime mover 32, the latter being an internal combustion engine of the reciprocating type in the particular construction illustrated. Since reciprocating-type internal combustion engines commonly used in oil fields usually burn gaseous fuels, the engine 32 will normally be a gas engine, but this is not essential since any type of engine or motor may be utilized to mount and drive the triplex pump Sli.

It will be noted from FlG. 1 in particular that the entire'triplex pump Sti is supported solely by the gas engine 32, the base 34 with which the latter is conventionally ,provided thus serving as the base for the entire enginetriplex combination so that no separate base is required. This results in a much more compact and lighter enginepump combination than anything hereto-fore available,

vwhich is an important feature.

Considering the mounting of the triplex pump 3u on the engine 32 in more detail, and referring particularly to FIG. 3 of the drawings, the housing of the triplex pump includes a crankcase 36 which is secured directly to the crankcase Sii of the engine, as by bolts (it). As will become apparent, all of the components of the triplex pump 3u are carried directly or indirectly by the triplex crankcase 36. Consequently, since the triplex crankcase 36 is bolted directly to the engine cranxcase 38, the en tire triplex pump 3d is supported solely by the engine 32.

The triplex pump 3u includes a crankshaft 42 which is disposed in the triplex crankcase 56 and which is mounted in two main bearings 44, FIGS. 3, 16 and 20, respectively disposed within main bearing housings 46 integral with the triplex crankcase. As best shown in FIG. 3 of the drawings, the triplex crankshaft 42 and the engine crankshaft l are positioned in axial alignment and lin end-to-end relation, the triplex crankshaft being couadres pled directly to the engine crankshaft by any suitable coupling means Sil. in the particular construction illustrated, the coupling means t) comprises an externally splined coupling member 52 which is suitably secured to the triplex crankshaft d2 and which is meshed with an internally splined flywheel 54 mounted on the engine crankshaft 43.

With the foregoing construction, the triplex crankshaft 42 is driven directly by the engine crankshaft 48 at the speed of the latter, the structure of the triplex pump 39 which enables it to operate at the same speed as the engine 32 being described in detail hereinafter. One important advantage of the direct coupling between the triplex pump Si) and the gas engine 32 is that the higher triplex speed results in a much smaller and lighter triplex pump which can be mounted directly on the engine, as hereinbefore described, thereby obviating any necessity for a separate base. Another important advantage of the direct coupling which the present invention makes possible is that no speed reducer and clutch are required, thereby further minimizing the size and weight, and incidentally the cost, of the engine triplex combination.

Triplex Pump Generally Continuing to refer primarily to FIGS. l to 3 of the drawings, the housing of the triplex pump 39 includes, in addition to the crankcase 36, a crosshead block 56 superimposed on the crankcase, a spacer block 58 superimposed on the crosshead block, and a cylinder block 6l) superimposed on the spacer block, the crosshead and spacer blocks providing a spacer means which spaces the cylinder block upwardly from the crankcase. The cylinder block 69 contains a pumping means, designated generally by the numeral 62 in FIG. 2, which includes three pumping units 6l, FIG. 4, operatively connected to the crankshaft 42 by corresponding connecting means 63, FIG. 3, which extend upwardly from the crankshaft through the crosshead block 56 and the spacer block 58 to such pumping units, as will be described in detail hereinafter.

The fluid to be pumped by the pumping means 62 is delivered thereto under pressure by a booster or charge pump 64 through an inlet passage 66, the pumped fluid discharged by the pumping means exiting through an outlet passage 63 which leads to the desired point of use. The inlet of the booster pump 64 is connected to a suitable source of supply by a supply passage 70. As will be discussed in detail hereinafter, the booster pump 64 is mounted on the end of the triplex pump case 36 opposite the end thereof which is bolted to the engine crankcase 38, the booster pump being coupled directly to the end of the triplex crankshaft 42 opposite the end thereof which is coupled to the engine crankshaft 4?.

The triplex pump 30 includes a scavenger pump 72 which scavenges pumped fluid leakage originating in the pumping means 62 from both the cylinder block 60 and the spacer block 58, the scavenger pump being shown schematically in FIG. 2 as having an inlet passage '74 communicating with the cylinder block and an inlet passage 76 communicating with the spacer block. Scavenging leakage originating in the pumping means 62 from the cylinder block 6l), as well as from the spacer block 5S, minimizes the amount of leakage entering the spacer block, and thus minimizes the amount of such leakage which must be handled by sealing devices associated with the connecting means 63 between the crankshaft 42 and the pumping means, as will be described. The scavenger pump 72 is a fluid operated pump which is actuated by iiuid discharged by the booster pump 64 through a supply passage '78, shown diagrammatically in FiG. 2. The leakage fluid scavenged by the scavenger pump 72 and the spent operating fluid emanating from the scavenger pump are discharged into a. common outlet passage 86 leading to a suitable point of disposal.

Contamination of the lubricating oil in the triplex crankcase 36 by vapor condensation is minimized by constantly scavenging vapors from both the crankcase and the spacer block 53. Vapor scavenging rom the spacer block 53 is particularly important when the pumped uid is crude oil, which is normally the case when triplex pump 3l) is utilized to supply power oil to Well pumps. The crude oil frequently contains light ends which form vapors in the spacer block 58 as the result of leakage thereinto from the pumping means 62. The sealing devices associated with the connecting means 63 cannot prevent all such light-end vapors from migrating downwardly from the spacer block SS into the crankcase 36, wherein they might condense to dilute the lubricating oil. Scavenging of vapors from both the crankcase 36 and the spacer block 58 minimizes such lubricating oil dilution, which is an important feature.

As shown diagrammatically in FIG. 2, vapor scavenging of the crankcase 36 and the spacer block 5S is effected by a Ventilating means 82 having an air inlet 34 communicating with the atmosphere and an air outlet 86 communicating with the crankcase. The scavenging or Ventilating air flows from the crankcase 36 into the spacer block 53 through a connecting passage 8S, the scavenging or Ventilating air being discharged from the spacer block through an outlet 90.

The Ventilating means 82 shown is fluid operated, the operating fluid being lubricating oil from the crankcase 36 which is supplied to the Ventilating means by a lubri- -cant pump 92 through a passage 94. The lubricating oil discharged by the Ventilating means 32 is returned to the crankcase 36 through a passage 96, FIG. 19. The lubricant pump 92 also supplies lubricating oil from the crankcase to various components of the triplex pump 3G which require lubrication, as discussed in detail hereinafter, an outlet passage 98 from the lubricant pump being shown diagrammatically in FIG. 2 for this purpose. The lubricant pump 92, of course, draws lubricating oil from the crankcase 36, being provided with an inlet 100 for this purpose.

Housing of Triplex Pump 30 As hereinbefore briefly outlined, the triplex housing includes four basic components, viz., the crankcase 36, the crosshead block 56, the spacer block 58 and the cylinder block 6?, the crankshaft 42 being carried by the crankcase, the pumping units 61 being carried by the cylinder block, and the connecting means 63 extending from the crankshaft through the crosshead and spacer blocks to the pumping units. The manner in which the four basic components of the triplex housing are secured together represents an important feature of the invention and will now be considered.

As will become apparent, the pumping units 61 apply upward hydraulic forces to the cylinder block 60, corresponding downward reaction forces being applied to the crankshaft 42 as the result thereof. The upward hydraulic forces applied to the cylinder block 66 are applied directly to the crankshaft 42, through the main bearings 44, to balance the downward reaction forces applied to the crankshaft. This is accomplished by the manner in which the cylinder block 69 is secured to the crankcase 36.

The cylinder block 6i) is secured to the crankcasc 36 by a plurality of connecting means tlZ which connect the cylinder block directly to the main bearing housings 46. As best shown in FIG. 16, each connecting means 1&2 includes an upper tie rod or bolt 104 which extends through the spacer block 5S and a flange on the cylinder block and thus secures the cylinder block to the spacer block. Each connecting means 132 also includes a lower tie rod or bolt lild which is at least approximately aligned with thc corresponding upper tie rod Each lower tie rod M6 extends through a flange on the spacer block 58, through the crosshead block 56, and through a portion of the crankcase 36 which is integral with one of the main hearing housings 46. Thus, as will be apparent from FIG. 16, upward hydraulic forces acting on the cylinder block 60 are transmitted directlyr to the main bearing housings 46 through the tie rods 104 and 1116, and thus are transmitted directly to the crankshaft 42 through the main bearings 44. Y

Another feature of the triplex housing resides in the particular structure of the crosshead block 56, which will now be considered. As best shown in FIG. 14, the crosshead block 56 is provided ytherethrough with crosshead guide bores 108 for crossheads 11i) respectively forming parts of the connecting means 63, vthe axes of the crossheadrguide bores being perpendicular toand in a plane containing the axis of rotation of the crankshaft 42.. The crosshead block 56 is split longitudinally into -two halves 112 having opposed surfaces 114 in planes parallel to the plane of the crosshead vguide bores, a plurality of shims 116 being disposed between the o-pposed surfaces 114 at each end of the crosshead block Se. l The two crosshead block halves 112 are secured together by bolts 118 extending throughA the shim sets 116. With this construction, when reboring ,of the crosshead guide bores 1418 is necessary to compensate for wear, enough shims are removed from the tvvok sets 116 to permit the crosshead block halves 112 to move toward each other sufficiently to permit reboring the crosshead guide bores 108 to their original diameters. Consequently, the rebore'd crosshead guide bores 1118 will accommodate crossheads 110 of a standard diameter, it being unnecessary to manufacture and stock oversize crossheads, which is an important feature.V l

It Will be noted lthat the crosshead block 56 is also 'a vseparate component of the triplex housing,` being a separate part from the crankcase 36 and the' spacer block 5S. Consequently, if the crosshead block 56 cannot be rebored to the original diameters of the crosshead guide :bores S, it may be replaced by a new crosshead block without replacing any other component of the triplex housing.

Connecting Means 63 Referring to FIGS. 3 and l1 in particular, each of the connecting means 63 which interconnects the crankshaft 4Z and one of the pumping units 61 includes a connecting rod 12e interconnecting the crankshaft andthe correspending crosshead 110. Each connecting rod 120 is connected at its lower end to the crankshaft 42 by a connecting rod bearing 122. Each crosshead 119 carries a wrist pin 124 and the corresponding connecting rod 1Z0 is connected to the wrist pin by a wrist pin bearing 126. The connecting rods 12th convert rotary motion of the crankshaft 42 into reciprocatory motion of the cross heads 11@ in an obvious manner. Y

The linear motion of the 'crossheads 111B is transmited to pump plungers 12S of the pumping units 61 by crosshead stems 131). The latter are rigidly connected to the crossheads 11e and extend axially upwardly therefrom through the spacer block S3 into engagement with the lower ends of the pump plungers 128, the latter being coaxial with the crosshead stems, the crossheads and the crosshead guide bores 1%.

As will be clear from FiGS. 3, 4 and 5 of the drawings, the pump plungers 123 are not connected to the crosshead stems 1313 in any Way, the lower ends of the pump plungers merely being engageable by the upper ends of the crosshead stems. Consequently, the connecting means 65 are capable only of producing the `upward strokes of the pump plungers 12d, but are incapable of producing the downward strokes thereof because of the absence of any structural interconnection between the pump plungers and the crosshead stems 139. As will become apparent, the upward strokes of the pump plungers 12S are the working strokes thereof, the downward strokes being the return strokes.

'In order to eifect the return stro-kes of the pump plungers 128, the discharge pressure of the booster pump 64 is constanly applied to the upper ends of the pump plungers through inlet check valves of the pumping units 61 which will be described hereinafter, the booster pump pressure being suiciently high to cause the pump plungers to follow thek crosshead stems downwardly under normal operating conditions. Forrexample, the discharge pres sure of the booster pump 64 may be of the order of 250 p.s.i.

As will be apparent, if foreign matter tends to cause the pump plungers 128 to tend to stick, or if the pump plungerrs tend to stick for any other reason, they merely remain at the upper vends of their strokes as long as their resistance to downward movement exceeds the down ward force applied tothe upper end thereof by the booster pump discharge pressure. Thus, the lack of any structural connection between the pump plungers 128 and the crosshead stems 130, andthe use of the booster pump discharge pressure to cause the pump plungers to follow the crosshead stems downwardly nn'der normal operating conditions, provide a safety means for disengaging the l.pump plungers from the connecting means '63 in the event that the pump plungers tend to stick to such `an extent as to damage various components of the triplex pump 30, such as the pumping means 62, the connecting means 63, the crankshaft 42 and the like. The importance of lthis feature will be recognized if itis kept in mind that the triplex pump 56 is required to operate for long periods of time with very little attention. Were it not for the foregoing means for disengaging the pump .plungers 128 from the connecting means 63 when excessive pump plunger friction develops, the triplex pump 3@ might be severely damaged before the next inspection and/ or servicing trip by the operator thereof.

Pumping Means 462 Generally Referring to FGS. 3 to 5 of the drawings, and particularly FIG. 4 thereof, the cylinder block 60 is provided with three side-by-s'ide liner bores 132 the axes of which are perpendicular to and in a plane containing the axis of the crankshaft 42. Each liner bore 132 contains a liner assembly 134 which provides a plunger bore 136 for the corresponding pump plunger 128. The axes of the plunger bores 136 are also perpendicular to and in a plane containing the axis of the crankshaft 42. The upper ends of the liner bores 132 are individually closed by independent closures 138 bolted, or otherwise secured, to the cylinder block 511. Consequently, each liner assembly 134 can be installed and removed independently of the others.

The cylinder block 611 is provided with inlet ports 14) respectively communicating with the liner bores 132 and is provided with diametrically opposite outlet ports 142 respectively communicating with the liner bores. Outwardly of the inlet and outlet ports 14) and 142 are inlet land outlet valve bores 144 and 146 in the cylinder block di?, the inlet and outlet valve bores respectively having at their inner ends annular seats 148 and 15@ respectively engageable by inlet and outlet check valves or check valve assemblies 152 and 154.

The outer ends of the inlet check valves 152 communicate, in a manner to be described in more detail hereinafter, with an inlet or intake passage 15e in an inlet or intake manifold 15?. The inlet passage 156 extends longitudinally of the inlet manifold 153 so that it communicates with the outer ends of all of the inlet check valves 152, the inlet passage 15d being suitably connected at one end to the inlet 'passage 6e leading from the outlet of the booster pump 64 to the Ipumping means 62. The inlet manifold 158 is regarded herein as forming a part of the cylinder block 60, but, in the particular construction aorzsse 1 l biasing the inlet check valves 152 into engagement with their respective seats 143. The outer ends of the bores 161) are closed individually by independent closures 16d bolted, or otherwise secured, to the inlet manifold 158. Thus, the inlet check valves 152 may be installed and removed independently of each other.

The cylinder block 6i) is provided with an integral exhaust or outlet manifold 166 having therein bores 168 located outwardly of and coaxial with the outlet valve bores 146 and communicating with the outer ends of the outlet check valves 154. The bores 163 are interconnected by an outlet or exhaust passage 176 which extends longitudinally of the outlet manifold 166 and which is suitably connected at one end to the outlet passage 68 leading to the point of use of the pumped fluid discharged under pressure by the pumping means 62. The outer ends of the bores 163 are individually ciosed by independent closures 172 bolted, or otherwise secured, to the cylinder block 60, i.e., to the portion of the cylinder block which forms the outlet manifold 166. Consequently, the outlet check valves 154 may be installed and removed independently of each other.

Liner Assembly 134 Referring to FIGS. 3 to 6 of the drawings, each liner assembly 134 includes a liner 174 and a liner head 176 threadedly connected together, the plunger bore 136 communicating at its upper end with a slightly larger bore 177 in the liner head. The liner head is provided with inlet and outlet ports 178 and 180 therein which communicate with the upper end of the plunger bore 136, through the bore 177, and which register with the corresponding inlet and outlet ports 141i and 142, respectively, in the cylinder block 60. A pin 182 on the corresponding closure 133 is disposed in a transverse groove 134 in the upper end of the liner head 176 to maintain the inlet and outlet ports 17S and 181) in register with the corresponding inlet and outlet ports 140 and 142, respectively. lt will be noted that the liner assembly 134 is symmetrical so that it can be installed in the corresponding liner bore 132 in either of two positions spaced 180 apart. Therefore, the groove 134 extends entirely across the upper end of the liner head 176.

Considering the manner in which the liner assembly 134 is sealed with respect to the cylinder block 6?, an elastomeric annular sealing element 186 of polytetrafluoroethylene, for example, is located below the inlet and outlet ports 173 and 150 and is disposed between an external annularshoulder on the liner 174 and an internal annular shoulder or seat formed on the cylinder block 66 and extending into the corresponding liner bore 132 therein.

lt will be noted that as the pump plunger 123 reciprocates in the plunger bore 136, the pressure applied to the upper end thereof alternates between the inlet pressure provided by the booster pump 64 and the discharge pressure, the difference between these pressures being several thousand p.s.i. r1`he alternately high and low pressure acting on the upper end of the pump plunger 12S also acts upwardly on an equal area of the liner assembly 13d, thereby tending to cause the sealing element 156 to alternately expand and contract. Such expansion and contraction of the sealing element 136, if permitted, would result in overheating of the sealing element due to intcrnal friction, thereby destroying this sealing element in a very short time.

To prevent the foregoing, the sealing element 136 is pressure loaded to a pressure value much higher than the maximum pressure to be sealed against, which maximum is the pressure produced by the pump plunger 12S immediately prior to opening of the corresponding outlet check valve 154. Such pressure loading of the sealing element 186 is accomplished by applying the discharge pressure of the pumping means 62 in the downward direction to the entire cross sectional area of the liner assembly 134.

For this purpose, the cylinder block 6i) is provided with a passage 188 which connects the upper end of the corresponding liner bore 132 to the bore 16S communicating with the outer end of the corresponding outlet check valve 154. Thus, the discharge pressure of the pumping means 62 is applied to the entire upper end of the liner head 176, the area to which the discharge pressure is applied in this fashion being larger than the area exposed to the peak pressure produced by the pump plunger 128 and being much larger than the areas of the annular shoulders between which the sealing element 186 is disposed. Consequently, since the lower end of the liner assembly 134 is exposed to substantially atmospheric pressure in the spacer block 58, as shown in FIG. 4, thc sealing element 186 is pressure loaded to a value several times the discharge pressure, and thus several times the maximum pressure to be sealed against, so that virtually no expansion and contraction of the sealing element 186 occur. Consequently, a long service life for the sealing element 186 is provided.

The same sealing principle is employed to provide a fluid-tight seal between the cylinder block 60 and the liner assembly 134 above the inlet and outlet ports 178 and 180 in the liner head 176. In this instance, an elastomeric annular sealing element 190, which may be of any suitable material, such as polytetrauoroethylene, is seated against an external annular shoulder on the liner head 176. The sealing element 199 is pressure loaded to a value far in excess of the maximum pressure to be sealed against by a loading ring 192 which encircles the liner head 176 and which has a small, downwardly facing, annular area 194 in engagement with the sealing element 19t). The loading ring 192 is provided with a large, upwardly facing, annular area 196 at its upper end which is exposed to the discharge pressure of the pumping means 62 through the passage 133 hereinbefore discussed, this upwardly facing annular area being several times as large as the downwardly facing annular area which engages the sealing element 190. The loading ring 192 is also provided with a downwardly facing, annular area 198 which is exposed to a much lower pressure than the discharge pressure of the pumping means 62, such lower pressure preferably being substantially atmospheric, as will be described in a subsequent paragraph.

With the foregoing construction, the loading ring 192 acts as an annular pressure amplifying element which applies to the sealing element 190 a pressure several times as large, e.g., three times as large, as the discharge pressure, and thus several times as large as the maximum pressure to be sealed against. Thus, virtually no expansion and contraction of the sealing element 19t) occurs as the pressure to be sealed against alternates between the intake and discharge pressure.

Considering the manner in which the annular area 19S of the loading ring 192 is exposed to substantially atmospheric pressure, it communicates with a passage means 200 formed partially in the loading ring itself, partially in the cylinder block 60, and partially rin the inlet manifold 158. The passage means 200 communicates with the corresponding bore 169 in the inlet manifold 15S, the opposite side of such bore communicating with a passage means 202 formed partially in the inlet manifold and partially in the cylinder block. The passage means 202 communicates, in turn, with the inlet passage 7- of the scavenger pump 72. The inlet passage 74 leading to the scavenger pump 72 is always at a pressure substantially equal to atmospheric, whereby substantially atmospheric pressure is applied to the annular area 19S of the loading ring 192 through the scavenger-pump inlet passage 74, the passage means 2112, the bore 16() and the passage means 20). The various components of the passage means 200 and 202 are not specifically identified on the drawings to avoid an excessively large number of reference numerals.

For the reasons set forth in the aforementioned prior patent, each pump plunger 128 tits relatively loosely in 13 its bore 136, there being an actual clearance therebetween. Consequently, there is substantially leakage of the pumped liquid downwardly through the'clearance between the pump plunger 128 and the wall of its bore 136. Virtually all ot this leakage vis drained voff into the inlet passage 74 of the scavenger pump 72 in an annular region near the lower end of the plunger bore, this being accomplished by providing a drain passage means 2414 in the liner 174 and the cylinder block 6i) which leads from the plunger bore to the passage 74. Annular sealing elements 206 and 208 carried by the liner 174 and respectively engaging the pump plunger 12S Iand the cylinder block 60 below the drain passage means 204' substantially completely prevent any of the pumped liquid' leaking 'downwardly pastthe pump plunger from entering the `spacer block 58, thereby minimizing .theamount of leakage which must be scavenged from the vspacer block. It will be noted that the sealing elements 206 and 208 are exposed to substantially atmospheric pressure from both above and below. Consequently, these sealing elements are capable of diverting most of the leakage past the pump plunger 128 into the drain passage means 204.

Since the majority of the pump plunger leakage is conducted directly to the scavenger pump 72 in the foregoing manner, and thus does not enter the spacer block 58, greater clearances can be provided between the pump plungers 1128 and the plunger bores 136 than 'would otherwise be'possible. Such greater clearances, which may be of the order of 0.002 inch for a one inch plunger, are essential to the high speed operation of the triplex pump `30 of the invention.

incidentally, it will be noted that leakage of the'pumped liquid originating at other points throughout the cylinder block 60 is also conveyed directly to the scavenger pump 72 and thus cannot' enter thespacer block 58. yFor example, the passage means 20th and 262 conduct leakage liquid passing the loading ring 192 directly to the inlet passage 74 of the scavenger pump 72. As will become apparent, the passage means 2th) and 202 also convey leakage liquid passing sealing means of the inlet and outlet check valves 152 and 15dJ to the inlet passa-ge 74 of the scavenger pump 72. Thus, very little of the pumped liquid leakage originating in the cylinder. block 6i? enters the spacer block 53, virtually all of it being conducted directly to the scavenger pump 72 by the inlet passage 7 4.

A ternative Liiier'Assembly FlG. l of the drawings illustrates an alternative liner assembly 216 which is similar to the liner assembly 134 and which includes a liner 212 and a liner head 214, a plunger bore 216 for one of the pump plungers 128 being provided in the liner. In this case, the liner head 21e is provided with an enlarged bore 218, considerably larger than the bore 177, with which inlet and outlet ports 22u and 222 communicate, these inlet and outlet ports respectively registering with the corresponding inlet and outlet ports 140 and 142 in the cylinder block 6i).

The enlarged bore 218 in the liner head 214 provides a larger clearance volume for the pump plunger 12S than that provided by the bore 177 in the liner head 176. Thus, the pump plungerclearance volumes may be varied readily as desired by substituting the liner assembly 21) for the liner assembly 134, or vice versa. Liner assemblies, not shown, having other pump plunger clearance volumes may also be provided. One set of liner assemblies may be substituted for another very readily by removing the closures 138 for the upper ends of the liner bores 132. As each liner assembly is removed from its liner bore 132, the pump plunger 12S carried thereby is automatically removed also.

In a similar manner, liner assemblies, not shown, having plunger bores and pump plungers of different diameters may beA used interchangeably. For example, it may be desired to change the pump plunger diameter to change the volumetric output of the triplex pump 3i),

sealed against such pressure.

1d Inlet Check Valve 152 Referring particularly to FIG. 4 of the drawings, each inlet check valve 152 includes a housing having an annular shoulder 224 engageable with the annular seat 14S. vThe retaining member 162 is threa-dedly connected 'to the housing of the inlet check valve 152 and is seated against an annular shoulder 226 thereon. The discharge pressure of the pumping means 62 is applied to the outer end of the retaining member 162, in a manner to be described, to hydraulically bias the inlet check valve 152 into engagement with its annular seat 14S. The area of the outer end of the retaining member 162is larger than the area 'of the inlet check valve 152 which is exposed to the extends outwardly from its bore in the inlet inanifold 158 intoa bore 228 in the corresponding closure 164. The outer end of Ithe bore 228 communicates with the outer end of the corresponding liner bore 132 through a passage means 23@ formed partly in the cylinder block 6), partly inthe inlet manifold 15S and partly in the closure 164. Since the outer end of the liner bore 132 contains iluid at the pressure Vproduced by the pumping means 62, the discharge pressure of the pumping means is applied tothe outer end of the retaining member 162 for the purpose hereinbefore described.

The housing of the inlet check valve 152 is sealed against the maximum pressure produced by the pump plunger 123 in the same way as the liner head 176 is More particularly, the housing of the inlet check valve 152 is encircled by an annular sealing element 232 which is compressed against an external annular shoulder on the housing of the inlet check valve by a pressure amplifying or loading ring 234.

v This loading ring has a small annular area 236 engaging the Aannular sealing element 232 and a large, oppos-itely facing annular area 233 exposed to the discharge pressure of lthe pumping means 62 present in the'passage means 236) by way of a branch passage 240 in the inlet manifold 158. The loading ring 234 is also provided with an annular area 242 which faces in the opposite direction from the area 238 and which is exposed to substantially atmospheric pressure through the previously described passage means 202.

Thus, the annular sealing element 232 is subjected to a pressure several times the maximum pressure produced by the pump plunger 128, in much the same manner that the liner head sealing element 19t) is subjected to an amplified pressure. Consequently, damage to the sealing element 232 through internal friction resulting from expansion and contraction in rhythm with the pulsating pressure between the inlet and outlet check valves 152 and 154i is avoided.

Considering the structure of the inlet check valve 152 in more detail, its housing includes a body 244 to one end ot which the retaining member 162 is threadedly connected and to the other end of which a cage 246 is threadedly connected. The body 2de carries a seat comprising concentric inner and outer rings 248 and 25u. Circumferentially spaced passages 252 extend longitudinally through the valve body 244 between the rings 243 and 25e, and a central passage 251i extends longitudinally through the valve body within the inner ring 248. The outer ends of the passages 252 and 25e communicate with the inlet passage 156 in the inlet manifold 158 through ports 256 in the retaining member 162.

Backiiow past the valve seat provided by the concentric rings 24S and 256 is prevented by a valve element, specitically a valve plate 258, carried by the cage 246 and biased into engagement with the concentric rings by a compression spring 26). The pumped liquid passes through the gate 246 either by way of circumferentially spaced peripheral ports 262 therein, or by way of an axial port 264 therein.

Because of the high speed at which the triplex pump pump 30 of the invention operates, the valve plate 258 must have as low a mass as possible to minimize its inertia, whereby the valve plate is capable of extremely high accelerations and decelerations in moving from its closed position to its open position and back again. Additionally, the valve plate 258 must have high structural strength to withstand the peak pressure differential of several thousand p.s.i. to which it is cyclically subjected. It has been found that the necessary low mass high strength may be attained by making the valve plate 258 out of titanium carbide.

Also, in order that the valve plate 25S may accelerate and decelerate at the necessary high rates, it is essential that friction between the valve plate and its cage 246 be reduced to an absolute minimum. This is accomplished by providing the valve cage 246 with three circumferentially spaced, longitudinally extending, tungsten carbide pins 266. As best shown in FIG. 8, each pin 266 is disposed partially within a longitudinal bore 268 in the valve cage 246, one side of the pin being exposed and being engaged by the periphery of the valve plate.

Not only does the foregoing guide means for the valve plate 258 minimize friction, but it also minimizes wear when the valve plate and the pins 266 are made of the materials indicated. When the valve plate 258 becomes excessively worn, it can readily be replaced by unscrewing the valve cage 246 from the valve body 244. At the same time, if necessary, the guide pins 266 can be removed from their bores 268 and replaced with new ones, knockout holes 267 being provided for this purpose.

As previously indicated, the valve plate 258 is sub` jeeted to a pressure differential which attains a value of several thousand p.s.i. and which varies cyclically between such value and a relatively low one. When the maximum pressure differential is applied to the valve plate 253, the total load thereon may be several tons, and such load must be borne by the concentric rings 248 and 25) forming the seat for the valve plate. However, the end faces of the rings 248 and 256, which end faces are ground flat in a common plane, must be as narrow as possible. Otherwise, an excessively high momentary pressure differential across the valve plate 258 would be required to initially disengage the valve plate from the end faces of the rings 248 and 256 due to the differential area across the valve plate produced by engagement thereof with such end faces. The high load which the end faces of the rings 248 and 25d must sustain, coupled with the necessary narrowness of these end faces, makes mandatory the use of a material like tungsten carbide for the rings 24S and 25o to provide an adequate service life.

The rings 248 and 258 are preferably secured to the valve body 2M by silver brazing, which must be carried out at a relatively high temperature. ln view of this, the tungsten carbide rings 24S and 256 must be mounted on the valve body 24d in such a manner that cooling of the assembly after brazing will not subject the tungsten carbide rings to tensile stresses as the result of differnetial contraction of the tungsten carbide rings and the valve body, which is preferably steel. Steel has a coefhcient of expansion about 2.4 times that of tungsten carbide and, if the resulting differential contraction upon cooling from the brazing temperature were permitted to place the tungsten carbide rings in tension, they would probably fracture.

The foregoing problem is overcome by insuring that, upon cooling from the brazing temperature, the steel valve body 244 is in tension and the tungsten carbide rings 248 and 25) are in compression, This is accomplished by inserting the rings 248 and 250 into cylindrical recesses 270 and 272 the circumferential walls of which contact only the outer circumferential walls of the respective rings, the inner circumferential walls of the rings being spaced from and out of contact with the valve body 244. Expressed more simply, both rings 248 and 250 are male parts and the valve body 244 is a female part with respect to both rings. The result of this construction is that cooling of the valve body 244 and the rings 24S and 250 after brazing subjects the steel of the valve body to high tensile stresses and subjects the tungsten carbide of the rings to corresponding compressive stresses, which is the desired relation.

After assembling the valve body 244 and the rings 248 and 250 in the foregoing manner, the end faces of the rings which are engageable by the valve plate are ground at in a common plane, the valve plate itself also being ground at. The outer ring 250 provides the desired fluid-tight seal when the valve plate 25S is seated thereagainst, the primary function of the inner ring 243 being to support the central portion of the valve plate.

Whenever the rings 248 and 25) become worn excessively, they may be removed from the valve body 244 upon heating thereof and may be replaced by new ones. The latter are assembled with the valve body 244 in the manner hereinbefore described.

It will be apparent that each of the inlet check valves 152 may be removed readily for servicing, replacement or the like, by removing the corresponding closure 164 and withdrawing the inlet check valve by withdrawing the corresponding retaining member 162. Since the retaining member is attached to the inlet check valve, the two components are removed simultaneously.

Outlet Check Valve 154 The outlet check valves 154 are identical to the inlet check valves 152, the only difference benig that the orientation of the outlet check valves relative to the pump plungers 128 is opposite to the orientation of the inlet check valves relative thereto. More simply, the inlet check valves 152 open inwardly toward the pump plungers 128 and the outlet check valves 154 open outwardly away from the pump plungers. Consequently, it is not necessary to consider the structure of the outlet check valves 154 in detail, it being necessary to consider only the reversed orientation thereof.

Referring particularly to FIG. 4 of the drawings, each outlet check valve 154 is disposed in its outlet valve Ibore 146 with the annular shoulder thereof which corresponds to the annular shoulder 226 of the inlet check valve 162 seated against the annular outlet valve scat 150. The discharge pressure of the pumping means 62 holds the outlet check valve 154 against its annular seat 150 in a manner to be described hereinafter, once such discharge pressure has been developed upon putting the triplex pump 30 into operation. The outlet check valve 154 is temporarily held substantially in its operating position mechanically by a pin 274 on the corresponding closure 172.

The housing of each outlet check valve 154 is sealed with respect to the cylinder block 60 in substantially the same manner as the inlet check valves 152 and the linel' heads 176. More particularly, an elastomeric annular sealing element 276 is seated against an external annular shoulder on the housing of the outlet check valve 154 and is engaged by a small annular area 278 of a pressure amplifying or loading ring 280 having an oppositely facing, large annular area 282 exposed to the discharge pressure in the bore 168. An annular area 284 facing in the opposite direction from the area 282 is exposed to substantially atmospheric pressure through a passage 286 in the cylinder block 6i) which communicates with the previously described passage means 266. Thus, the pressure applied to the sealing element 276 by the loading ring 280 is several times the peak pressure produced by the pump plunger 128, whereby expansion and contraction of the sealing element, and consequent overheating thereof, are prevented.

`Considering the manner in which the outlet check valve 154 is hydraulically maintained in engagement with its annular seat d, it will be noted that the discharge pressure in the bore 168 acts inwardly, i.e., toward the pump plunger 123, on an area substantially equal to that encompassed by the outermost periphery of the loading ring Zat). The peak pressure produced by the pump plunger 128 acts outwardly on a smaller area, viz., that enclosed by the annular sealing element 276. Even though the peak pressure produced by the pump plunger 12S is slightly higher than the discharge pressure in the bore 168, the area differential mentioned is suhicient to insure seating of the outlet check valve 154. In other words, the area 2284 exposed to substantially atmospheric pressure is sutliciently large that a high net pressure force dilterenti'al is always acting in a direction to maintain the outlet check valve 154 in engagement with its annular seat 15G.

Unloading Medns Referring particularly to FIG. 4 of the drawings, each inlet check valive 152 is provided with an unloader 28S which, upon command, will hold the corresponding valve plate 258 oil the seat therefor provided by the concentric rings 24S and 250. The unloaders 28S may be actuated to remove the pumping load of the pumping means 562 from the gas engine 32, wherefore no clutch is necessary between the gas engine and the triplex pump 3d, as hereinbefore discussed. Also, if desired, ythe unloaders 288 may be utilized to kill any residual pressure between the inlet check valves 152 and the outlet check valves 154 when it is necessary to open up the cylinder lblockttl for any reason.

Each unloader 238 comprises a piston 290 disposed in a bor'e 292 in the corresponding retaining member "12, the bore 292 being coaxial `with the corresponding inlet valve bore 144. Projecting axially from the piston 297i) 'is `a rod V294- which terminates in a pin 296 extending axially into the central passage 254 in the body 244 of the housing of the corresponding inlet check valve 152. The pin 296 is reciprocable in a lspider 2.98 in the central passage '254 and terminates in an elastomeric tip 309' engageable Vwith the corresponding valve plate 258, the purpose of such tip `being toprevent damage to the valve plate.

The linner side of each piston 290 is constantly -exposed to substantially atmospheric pressure through a passage means 302 in the inlet manifold 158 and the corresponding retaining member 162, the passage means 362 communicating with the 'passage means 202 leading to the inlet fof the scavenger'pump 72 by way ofthe inlet'passa'ge i4 herein-before described. The outer side of each Vunloader'piston 290 communicates with the control passage means -354 in the inlet manifold 158 and the correspondingretaining member 162. Normally, the control passage meansltl is at substantially atmospheric pressure, with the resultthat the unloader pistons l291i are -in their outermostpositions due to the vfact that the discharge pressure of the booster pumped is applied to theinner endsofthe rods 294 and the vpins 296. Whenever it isdesired to hold the inlet check valves 152'open, the control passage means 304 ispressurized to an extent suflicient to move the unloader pistons 2911 inwardly to laccomplish this.

A suitable control valve, not shown, may be provided to connect' the controllpassage-means 364 to substantially atmospheric pressure, orto a source of fluid under -sufticiently highpressure to effect unloading. For example, the control passage meanst may' be connected t0 the outlet of Athe booster pump 64 whenunloading is desired. Alternatively, the control 'passage means 304 Amay beconnectedto an accumulator, not shown, containing 'fluid under-sufcient pressure for the purpose.

is Sealing Means for Crosshead Stems 130 As hereinbefore discussed, the bulk of the leakage of the liquid being pumped is scavenged directly from the cylinder block 60 through the inlet passage 74 of the scavenger pump 72. However, some pumped liquid leakage nevertheless does enter the spacer block 5S and must be prevented from entering the crankcase 36 along the crosshead stems in order to prevent contamination of the lubricating oil in the cranlrcase. Each crosshead stem 130 is provided with a sealing means or sealing assembly Stia for this purpose.

The problem of sealing the crosshead stems 13.0 lis complicated by the fact that such stems are subjected to considerable random sidewise movement, both lateral and angular, as they reciprocate. Such random sidewise movement is Idue to the fact that it is inherently impossible to convert rotary crankshaft motion into absolutely linear reciprocatory motion, particularly at the high crankshaft speeds attained with the present invention. The random sidewise movement of the crosshead stems 13@ is further increased because the crosshead stems are designed to float laterally to some extent in their guide bores 103, as will be discussed hereinafter. Thus, the sidewise movement or the crosshead stems 13.0 is quite large.

Elastomeric annular sealing elements Will not seal reciprocating or rotating members properly unless the seal-` ing elements and the reciprocating or rotary members are maintained concentric within very close tolerances. The present invention solves this problem in connection with the reciprocating crosshead stems 13d by so mounting the sealing assemblies 3% that they are free to follow the random sidewise motion of the crosshead stems, Wherefore elastomeric annular sealing elements incorporated in the sealing assemblies remain concentric with the crosshead stems at al1 times. The float-ing sealing assemblies 306 thus represent an important feature of the vpresent invention.

yReferring particularly to FIGS. ll and l2 of the drawings, each sealing assembly `3% includes an annularsealing sleeve or seal housing 36S, shown as made Yin two parts disposed in end-to-end relation and suitablysecured together, 4having therein two axially spaced Vbearings 3101 and 312 through which the corresponding crosshead stem 130 slidablyextends. The seal vlmusing 508 extends into a bore 314 vand a counterbore 316 in the `spacer block 5,3 and .is provided within the counterbore 316 fwithan external annular flange 318 having elastomeric mounting rings 320 disposedthereabove and therebelow. Thelower mountingtring 32? is disposed between the annular lflange 31S and the annular'shoulder formed at the junction of the counterbore 316 and the bore314. vThe upper, mounting ring 326 isvdispcsed between the annular vflange 3,1/3 and an annular retaining member 322 extending-intofvand suitably secured in the upper-end of [the counterbore y31,6. Substantial clearances are provided between the Seal housing 303. and the circumferential wallof the :bore 314, between the annular ange 318 and the circumferential wall ot thecounterbore 316, and betweenthesealhousing and the retaining member 32.2.

With the foregoing construction, the elastomeric mounting rings SZtlpermit the seal housing 30S to move `both laterally and yangularly with the cross head stemlttfin response to such movement of the crosshead stem. Consequently, elastomeric. annular se aling elements carried vby the seal housing 3.03, which sealing elements will-be describedhereinafter, are maintained substantially `concentric with ,the crossheadstem 13.@ despite random, sidewise movement of the latter', which is an important .feature The mounting rings 32@ do permit slight axial movement vof the seal housing 368, butthis is negligible due ,to the fact that the mounting rings are maintained in` astate .of compression by the retaining member' 322.

It will be noted that the mounting rings SZtlalsokact as-sealing-rings-between the spacer block'S and the seal housing 308. Consequently, they prevent leakage from the spacer block 58 into the crankcase 36 externally of the seal housing 308.

The seal housing 338 carries a lower, downwardly facing lip seal 324 and an upwardly facing lip seal 325 above the seal 324, both of these seals engaging the crosshead stem 130 and remaining substantially concentric therewith at all times due to the floating mounting of the seal housing provided by the mounting rings 320. The downwardly facing seal 324 strips lubricating oil from the crosshead stem 130 as the crosshead stem moves upwardly, leaving only an extremely thin iilm of a few microns in thickness. Similarly, the upwardly facing seal 326 wipes leakage liquid from the crosshead stem 13d as the crosshead stem moves downwardly so as to prevent such leakage liquid from entering the crankcase 36, any film of leakage liquid left on the crosshead stem by the seal 326 also being extremely thin. Since the seals 324 and 326 act unidirectionally, the microscopic Iilrns they leave on the crosshead stem 139 are virtually undisturbed by the respective seals as the films are withdrawn from the space between the seals. Thus, there is substantially no tendency for the lubricating oil and the leakage liquid in the two films to mingle since each film is withdrawn from the space between the seals 324 and 326 virtually intact.

Further, the axial spacing of the seals 324 and 326 is slightly greater than the stroke of the crosshead stem 135), the difference between the seal spacing and the crosshead stem stroke being indicated by the double-headed arrow 32S in FIG. 1l. Consequently, neither of the seals 324- and 326 ever comes into engagement with the portion of the crosshead stern 13) which is engaged by the other of such seals. Therefore, it is impossible for the seal 324 to strip oi any of the leakage liquid ilm passing the seal 326 and thus pump it into the crankcase 36.

It will be noted that the seals 324 and 326 are between the bearings 3H) and 312. Thus, the lower bearing 310 is lubricated by lubricating oil from the crankcase 36, the lubricating oil reaching this bearing from the corresponding crosshead 110. The manner in which the lubricating oil is delivered to the crosshead titi will be considered hereinafter. rThe upper bearing 3i2 is lubricated by the leakage liquid, such liquid normally being crude oil, which has adequate lubricating qualities for the purpose. Also, as will be discussed hereinafter, lubricating oil from the crankcase 36 is metered into the leakage liquid in small quantities and this helps to lubricate the upper bearing 312.

Carried by the seal housing 363 above the upper bearing 312 and engaging the crosshead stern 136 is another upwardly facing lip seal 339. This lip seal has two functions. First, it wipes abrasive particles which may be entrained in the leakage liquid from the crosshead stem i3@ as it moves downwardly into the upper bearing 312, thereby protecting such bearing. Second, the seal 33t) co-operates with the seal 325 to provide a pumping action for the purpose of circulating relatively clean liquid through the space between the seals 326 and 33t?, thereby lubricating these seals and the intervening bearing 312 and llushing away any foreign matter which may tend to accumulate on the upper seal 330.

'I'he seals 326 and 330 co-operate to pump leakage liquid into the space therebetween from an annular reservoir 332 carried by the sealing housing 303, such reservoir being formed by suitably mounting a sleeve 334 on the seal housing. The sleeve 334 carries a cap 335 for the reservoir 332, such cap providing a clearance 338 around the crosshead stem i3d through which pumped fluid leakage may ow downwar ly along the crosshead stern into the reservoir.

The seals 326 and 33@ pump liquid from the reservoir 332 into the space therebetween through an annular channel 342 and a port 344 in the seal housing 3%. Telescoped over the seal housing and covering the channel 2@ 342 is an annular iilter 346 ot sintered metal, or the like. ri`hus, the liquid pumped into the space between the seals 326 and 339 is relatively clean, which is an important feature.

Considering how the seals 326 and 33d provide the pumping action mentioned, a substantial quantity of liquid is carried upwardly through the upper seal 330 during each upward stroke of the crosshead Stem 130. However, since there is only a microscopic liquid tilm on the crosshead stem below the seal 326, no liquid is carried into the space between the seals 326 and 330 by the crosshead stem during its upward movement to replace that carried out by the crosshead stem past the upper seal 339. This results in a slight negative pressure between the seals 326 and 330 during the upward stroke of the crosshead stem 130, with the result that liquid is drawn from the reservoir 332 through the filter 346 into the space between the seals 326 and 33S.

The liquid carried upwardly past the upper seal 330 by the crosshead stem 13d is wiped olif, except for a very thin ilm, during the subsequent downward stroke of the crosshead stem, the liquid wiped off in this fashion dowing back into the reservoir 332. In the process, it ushes foreign matter from the upper side of the upper seal 330 which is an important feature.

As previously mentioned, lubricating oil from the1 crankcase 35 is Constantly added to the leakage liquid in each sealing assembly 336 so that the liquid in the reservoir 332 contains a high proportion of clean lubrieating oil. The lubricating oil from the crankcase 36 is metered into each reservoir 332 at a rate of about onethird quart every twenty-four hours, for example.

Considering how the lubricating oil from the crankcase 36 is supplied to each reservoir 332, the spacer block 58 is provided with lubricating oil passage means 348, FIGS. 12 and 25, each of which, as shown in phantom in FIG. 1l communicates with the space between the mounting rings 323 associated with the corresponding seal housing 33S. From each of these spaces, the lubricating oil llowS upwardly through a passage means 350 in the corresponding seal housing 303 into a standpipe 352 within the corresponding reservoir 332.

In order to meter the lubricating oil into each reservoir 332 at the desired low rate for the particular lubricating oil pressure provided, which may be of the order of 60 p.s.i., the lubricating-oil flow rates into the three passage means 343 are correspondingly limited in a manner which will now be described. The lubricating oil discharged by the lubricant pump 92 enters the spacer block S3 through a passage means 492, FIGS. l5 and 25, and flows into a counterbore 494 in the spacer block, the outer end of this counterbore being closed by a plug 496. The counterbore 494 communicates at its inner end with a bore 498 into which is threaded a housing 590 removable through the counterbore 494 upon removal of the plug 496. The housing 5663 carries a sintered metal lter 562 and provides an orice 534. The lubricating oil entering the counterbore 494 by way of the passage means 492 ows first through the filter 502 and then through the orifice S84, the discharge pressure of the lubricant pump 92 being throttled to a very low value by the orifice. How ever, the pressure on the downstream side of the oriice 504 is still too high to meter lubricating oil to the reservoirs 332 at the desired low rates.

From the inner end of the bore 493, the lubricating oil, at its now relatively low pressure, ows into a lateral passage means S65, FIG. 25, which communicates with three spaced, parallel bores 538 in the spacer block 58. The bores 568 respectively communicate at their inner ends with the aforementioned passage means 34S leading to the respective spaces between the mounting rings 320 associated with the respective seal housings 303. Removably threaded into each bore 56S is a housing 510 having in its inner end an axial bore 5l2 which communicates with the corresponding bore 508 through radial 

6. IN COMBINATION: A MAIN PUMP HAVING A MAIN PUMP HOUSING PROVIDED WITH AN INLET AND AN OUTLET AND HAVING A MAIN PUMP SHAFT PROVIDED AT ONE END THEREOF WITH A MAIN PUMP SPROCKET; A BOOSTER PUMP INCLUDING A BOOSTER PUMP HOUSING PROVIDED WITH AN INLET AND AN OUTLET AND HAVING THEREIN A BOOSTER PUMP SHAFT COAXIAL WITH SAID MAIN PUMP SHAFT, SAID BOOSTER PUMP HOUSING BEING MOUNTED ON SAID MAIN PUMP HOUSING, SAID BOOSTER PUMP SHAFT AND SAID MAIN PUMP SHAFT BEING ARRANGED IN END-TO-END RELATION AND SAID BOOSTER PUMP SHAFT HAVING THEREON AT ONE END THEREOF A BOOSTER PUMP SPROCKET AXIALLY ALIGNED WITH AND ADJACENT SAID MAIN PUMP SPROCKET, SAID MAIN AND BOOSTER PUMP SPROCKETS BEING OF THE SAME DIAMETER, SAID OUTLET OF SAID BOOSTER PUMP BEING CONNECTED TO SAID INLET OF SAID MAIN PUMP; AND AN ENDLESS, CIRCULAR CHAIN COAXIAL WITH SAID MAIN AND BOOSTER PUMP SPROCKETS AND MESHED WITH SAID MAIN AND BOOSTER PUMP SPROCKETS SO AS TO TRANSMIT ROTATION OF SAID MAIN PUMP SHAFT TO SAID BOOSTER PUMP SHAFT. 